The implementation of trick-play modes within digital video systems is a problem which is becoming more important as digital video-based systems enter the marketplace. Emerging consumer video products such as video on demand (VOD), video CDs, and other similar systems may compete with the VHS tape market as providers of feature-length movies. However, unlike analog-based replay methods, digital video systems represent a challenge in the reproduction of video images at speeds other than normal play speed. Such “off speed” reproductions being known as trick-play which may provide images at various speeds, for example, fast-forward, fast-reverse, freeze-frame etc.
In European Patent application number EP A 0625857 a video server is disclosed which provides video signals to a user responsive to control signals received therefrom. Application EP A 0625857 teaches the use of a real time signal and an exemplary 10 times speed special signal which are linked to permit selection therebetween without program discontinuity. The special signal is processed such that its transmission rate is no higher than that of the real time signal. Special signal processing is acheived by omitting inter-frame coded data from the MPEG bistream. Application EP A 0625857 recognizes the requirement to restrict the transmission rate of the trick play or special signal and as a consequence of omitting inter-frame coded data must recalculate time stamps.